The present invention relates to a fluid pump including a pumping mechanism and a drive source in a housing, the pumping mechanism being run by rotation of a rotary shaft and the drive source driving the rotary shaft of the pumping mechanism.
Japanese Unexamined Patent Publication No. 8-78300 discloses a fluid pump. In this prior art, in a process for manufacturing a semiconductor, a vacuum pump is used for exhausting gas reaction product from a semiconductor machining apparatus. In the vacuum pump, gas reaction product can be solidified therein. The solidified matter is exhausted outside the vacuum pump together with gas reaction product during the operation of the vacuum pump is run. Therefore, unless an excess gas reaction product is solidified, continuous operation of the vacuum pump is not interrupted.
However, after the operation of the vacuum pump is stopped in such a state that the solidified matter exists in the vacuum pump, when the vacuum pump is operated once again, the vacuum pump requires an excess amount of starting torque thereof. Thereby, it may become impossible that the vacuum pump re-starts depending on the drive source such as an electric motor. That is, if the solidified matter gets into a clearance between a rotary member and a housing, the clearance is reduced as a consequence of a drop in temperature of the vacuum pump. Thereby, the rotary member and the housing are pressed and adhered to each other so as to sandwich the solidified matter.
In order to solve the above problem, the vacuum pump is conventionally overhauled before re-starting. Thereby, the solidified matter that is accumulated in the vacuum pump is removed.
However, in a prior art, every time the vacuum pump is re-started, the vacuum pump has to be overhauled. This overhaul causes trouble to an operator.